Abstract
Recently, Wachtman and his colleagues showed that a good description of the temperature dependence of the Young's modulus of several oxides is where is the modulus at absolute zero and and are constants. Wachtman and his colleagues pointed out that they had no theoretical basis for this equation, but demonstrated that it worked very well over a large temperature range (1000°K), and they discussed the physical basis for the parameters and . In this paper we show that the form of their equation for is equivalent to an equation for the bulk modulus derived from the Mie-Grüneisen equation of state. The Wachtman empirical equation for Young's modulus apparently is valid only when the variation of Poisson's ratio with temperature is small, for in that case is equal to , where is the bulk modulus.
- Received 27 October 1965
DOI:https://doi.org/10.1103/PhysRev.144.553
©1966 American Physical Society